Four-section reflector



Nov. 17, 1936. c. A. MICHEL FOUR-SECTION REFLECTOR il ep 5 I 2 Sheets-$heet l C. A. MICHEL FOUR-SECTION REFLECTOR Nov. 17, 1936.

2 Sheets-Sheet 2 Filed Sept. 3, 1955 Patented Nov. 1 7, 1936 UNE'E'ED STATES PATENT OFFICE FOUR-SECTION REFLECTOR Application September 3, 1935, Serial No. 38,955 .1 Claim. (01. 240-4136) This invention relates to reflectors used in automobile headlamps and is an improvement over the reflector shown and described in Patent No. 2,033,387, dated March 10, 1936, issuing from an application of C. A. Nlichel et al., Ser. No. 716,574 filed March 21, 1934. That application discloses a reflector having five horizontal sec-- tions, located one above the other, and whose outline as a whole is generally parabolic. The beams directed by these sections from a source of light form a superposed pattern in which the top, central portion is the area of highest light intensity or the hot spot, the upper edge of the whole being abruptly cut off in .a horizontal line. The central sections of the reflector are those which supply the hot spot and it is therefore essential to have those sections accurately positioned and to have the proper respective vertical location of these central sections.

With the use of the five-section reflector, as disclosed in the above mentioned application, difficulty was encountered in maintaining the correct vertical relation between the central and the adjacent zones in production and since these zones form the hot spot, their location must be accurate. Also the present trend of headlamp design is toward the use of those having smaller diameter which necessitates reflectors of smaller diameter and with these it is even more difficult to maintain accurate vertical positioning of the reflector zones.

The present reflector was designed to give more accurate positioning of the reflector zones and is particularly adapted to use in the smaller diameter headlamps. The vertical and horizontal center lines of the center portion and the portion just below the center are now one since these portions now are one zone which eliminates the necessity of superposing the two sets of axes. The upper portion of the central section of the present design also yields a wider beam than the previous design since the filament is slightly behind focus. This has the advantage that there is a little more illumination of the roadside to aid in avoiding parked cars and other objects.

In order to have the various zones of the reflector superpose their beams to form a composite pattern, the focal points of the different zones will lie at spaced points substantially on the axis of the reflector. With these spaced foci it is advantageous to have the reflector as a whole as insensitive to inaccuracies in the positioning of the filaments as possible and this particular type is relatively insensitive.

For a better understanding of the nature and objects of this invention, reference is made to the following specification wherein there is described the embodiment of my invention which is illustrated in the accompanying drawings, in which:

Fig. 1 is a front elevation of my improved reflector.

Fig.2 is a vertical section taken on the line 2-2 of Fig. 1.

Fig. 3 is an enlarged view of the center of Fig. 2 showing in exaggerated relation the foci and axes of the various sections.

Figs. 4-7 show the type of beams projected by the various sections of the reflector with the lower filament energized.

Fig. 8 shows the composite beams formed by superposing the various beams of Figs. 4-7.

Figs. 9-12 show the beams projected by the various sections of the reflector with the upper filament energized.

Fig. 13 shows the composite beam formed by superposing the various beams of Figs. 9-12.

The reflector generally designated at I0 is of substantially parabolic shape having an opening I2 in the central portion for the bulb and the usual flanged edge 14. The body of the reflector is made up of four transverse, superimposed zones A, B, C and D. Each of the zones is a portion of a surface of revolution and is preferably of parabolic contour.

In Fig. 3 the relation of the axes and focal points of the various zones is clearly set forth. Zone A has its axis inclined downwardly 2 rotated about its focal point which is shown at FA. Zone B has its axis B-B inclined to a smaller extent, rotated about its focal point FB. Zone C has its axis at C-C and is inclined at approximately the same angle as zone B, which is being rotated about its focal point FC. The axis D-D of zone D has an inclination downward of A, rotated about the line of intersection 20 of sections C and D in a vertical plane and the the focal point of this zone is shown at FD.

It should be noted with respect to the relative location of the focal points that the focal points of zones A, B and C lie in substantially a straight horizontal line but that FD is spaced a short distance below the line through the other three. This is partially due of course to the fact that the zone D is rotated around the line of intersection of zones C and D instead of around its focal point as were the other zones.

The two sources of light, S and S, which eminate from the two filaments of a conventional two-filament lamp, are shown diagrammatically in Figs. 1 and 2. These are small triangular filaments coming to a point at the front and expanding toward the rear and lying parallel and one directly above the other. The lower filament S lies slight above the main horizontal axis of the reflector and the filament S is spaced thereabove, both of course lying on the vertical axis of the refiector. The center line of the filaments is shown on Fig. 3 by the vertical center line and it should be noted that the two upper sections A and B have their focal points to the rear of this center line while sections C and D have their focal points to the front.

The downward tilt of the axis of sections B and C is given to insure that the tops of the beams from these zones shall come up to, but not project above, the horizontal. The same end may by accomplished by tilting either the headlamp or the reflector forwardly but this is often regarded as unsatisfactory both from the standpoint of appearance and difficulty of adjustment of headlamps in service.

In Figs. 4-7 are shown the respective beam patterns of sections A, B, C and D which these sections give when the lower filament is lit. It will be noted that none of the patterns project appreciably above the horizontal. The patterns from B and C provide the illumination for the hot spot and the tops of these are practicaly horizontal. In the pattern for C there is a wide portion just below the horizontal of lesser intensity than the central portion which was formerly mentioned.

Fig. 8 shows the composite pattern when the beams of the various sections AD are superposed as would result from actual practice. It might be mentioned that this beam is the long range or country driving beam.

In Figs. 9-12 are shown the respective beam patterns of the same sections when the upper filament is lit. In this case the patterns are lower but still the two central sections provide the hot spot illumination.

Fig. 13 shows the composite beams of Figs. 9-12 and is similar to Fig. 8. This beam is the short range or city driving beam.

This reflector may be used with many of the conventional type of lenses but is particularly adapted to be used with the lenses disclosed in Figs. 28 to 32 of the application of John L. Koubek, Ser. No. 679,296 filed July '7, 1933 or that disclosed in an application of John L. Koubek, Ser. No. 676,821 filed June 21, 1933.

I claim:

In a reflector for headlamps, a shell formed of a plurality of superimposed, transverse, parabolic, plain zones having their focal points spaced apart, the focal points for the three upper zones lying in a straight line, the focal point for the lowest zone lying below this line, the axes for each of these zones slanting downwardly, the axes for the three upper zones being rotated about their focal points and the axis for the lowest zone rotated about the line forming the junction between two zones.

CLARENCE A. MICHEL. 

